1. Field of the Invention
The present invention relates to an optical fiber fixing device and a related method for fixing an optical fiber on a V-grooved block in an optical fiber fusion splicing apparatus.
2. Description of the Related Art
An optical fiber fixing device is disclosed in Japanese Patent Publication No. 10-39161 and reproduced herein in FIGS. 1 and 2. As shown in FIG. 1, an optical fiber fixing device 101 is comprised of a main frame 103, a lid 105, a V-grooved block 107, a stepping motor 109, a presser block 111, a support table 113, a link mechanism 115, a tension spring 117 and an actuator 119. The V-grooved block 107, the stepping motor 109 and the actuator 119 are disposed on a main frame 103 side. The presser block 111, the support table 113, the link mechanism 115 and the tension spring 117 are disposed on the lid 105 side.
The presser block 111 is mounted to a lower end of the support table 113. The support table 113 is pulled upward at all times due to a resilient force of the tension spring 117 and is vertically moved via the link mechanism 115 by the stepping motor 109. The link and is vertically moved via the link mechanism 115 by the stepping motor 109. The link mechanism 115 is supported on the lid 105 to rotate around a fulcrum S. The tension spring 117 has one end coupled to the lid 105 and the other end coupled to the support table 113.
Under such a construction, as shown in FIG. 2, an optical fiber 121 is fixed in place between the V-grooved block 107 and the presser block 111. After the lid 105 has been closed toward the main frame 103, the link mechanism 115 is driven by the stepping motor 109 to allow one end of the link mechanism 115 to be pushed upward. This causes the other end of the link mechanism 115 to be lowered, thereby compelling the support table 113 and the presser block 111 to be pushed downward. When this takes place, the V-grooved block 107 is driven by the actuator 119 to be pushed upward. Since the optical fiber 121 is pressed downward by the presser block 111 and pushed upward by the V-grooved block 107, the optical fiber fixing device 101 fixes the optical fiber 121 in place between the V-grooved block 107 and the presser block 111.
However, this fixing mechanism has several drawbacks. For example, due to the use of such a complex fixing mechanism, manufacturing costs and maintenance costs increase. The optical fixing device 101 uses, as the fixing mechanism, the V-grooved block 107, the stepping motor 109, the link mechanism 115, the tension spring 117 and the actuator 119. Accordingly, the manufacturing cost and the maintenance cost of the optical fiber fixing device 101 increase.
Further, due to the use of the spring as one part of the fixing mechanism, unevenness occurs in the force required for pressing the optical fiber onto a V-grooved block. The optical fiber fixing device 101 urges the support table 113 upward at all times using the tension spring 117. Since the resilient force of the spring normally varies depending on its age (i.e., the amount of times it has been used) and the ambient temperature, etc., a force required for the link mechanism 115 to push the support table 113 downward differs in every fixing operation. Consequently, unevenness occurs in the force required for pressing the optical fiber 121 onto the V-grooved block 107.
Still further, due to the absence of a mechanism for controlling the moving speed of the fixing member, the optical fiber is not fixed in place between a fixing member (presser block) and a V-grooved block by taking a thickness of the optical fiber into consideration. In general, the thicker the optical fiber is (i.e., the larger the number of core wires of the optical fiber), the stronger repulsion force the optical fiber has, wherein the repulsion force is generated at the time of bringing the fixing member into contact with the optical fiber to push the fixing member upward. For this reason, in a case where the optical fiber is thick, if the fixing member is lowered at a low speed, the fixing member is pushed back in response to the repulsion force of the optical fiber before the fixing member pushes the optical fiber onto the V-grooved block 107. Accordingly, in the case where the optical fiber is thick, the fixing member needs to be lowered at a higher speed than that at which the fixing member is lowered when the optical fiber is thin.
Even further, due to the absence of a mechanism for automatically confirming a fixed status of the optical fiber, it takes much time to confirm such a status. When confirming the fixed status of the optical fiber 121, an operator needs to open the lid 105.